Air sander grinder is a hand held grinder that is driven by air pressure. It has an eccentric mounting that vibrates by air pressure, and this vibration is sent to the grinding disc at the bottom, and an air chamber is placed on the upper part of tool with a set of movable leaves inside for the air pressure to form the driving effect. The present invention improves the structure of the mounting and eccentric mounting.
The conventional structure of the mounting is shown in FIGS. 1 and 2, the entire air chamber mounting 10 has an air chamber 11 installed therein. The air chamber has an air inlet 12 and air outlet 13 and is formed by processing a metal block. Except, the structure of this air chamber mounting has the existing issues described as follows:
1. Because the inside of the central air chamber 11 of the mounting must be cleared out entirely, it creates large amount of metal waste, besides increasing the processing time and not efficient and not cost effective, it also creates the environmental protection issue such as waste processing.
2. Moreover, the air outlets 12, 13 must be processed by lathing, milling and drilling, therefore, it generates waste, increases the processing time and cost as mentioned above, which does not meet the preferred practicability of the industry.
3. The current development for the air sander grinder is in the direction of lighter structure in convenience of long period operation for the users. Therefore, the metal structure of the conventional air chamber mounting mentioned above obviously has the heavy weight problems and creates more burdens when using it.
Secondly, the top section of the structure of the eccentric mounting of the air sander grinder is usually a mandrel, and the bottom section is an eccentric block, and the inside of the eccentric block must be machined to form a carrier slot for the axle of the grinding disc to place inside. One of the structures of the conventional eccentric mounting is to make the mandrel and eccentric block separately, then weld them together, however, because the welding part of the eccentric block is placed on top wall of the carrier slot, and the thickness of the wall is thin. Therefore, it fails to create sufficient welding strength, and to increase the thickness must increase the size and the weight of the entire structure, which is not good for developing a lighter product. The second structure of the conventional eccentric mounting 20 as shown in FIGS. 3 and 4 is to make the mandrel 21 and eccentric block 22 in one single metal block; except, this conventional structure has the existing issues found in the practical application.
1. Because the ratio of the mandrel 21 and eccentric block 22 of the eccentric mounting 20 is quite different, using one single metal material needs to be made based on the biggest outer diameter of the eccentric block 22, which largely increases the cost of the material. And the following process for making a mandrel and eccentric block must be formed by lathing and milling, not only generating large amounts of metal waste, but also showing the lack of efficiency during the forming process. The cost of processing machine is quite expensive; it does not meet the preferred practicability of the industry.
2. The current development for the air sander grinder is in the direction of lighter structure for the convenience of long period operation for the users. Therefore, the metal structure of the conventional mandrel 21 and eccentric block 22 is obviously heavy and is more burdensome while being used
Thus, to overcome the aforementioned problems of the prior art, it would be an advancement if the art to provide an improved structure that can significantly improve the efficacy.
To this end, the inventor has provided the present invention of practicability after deliberate design and evaluation based on years of experience in the production, development and design of related products.